Background

The first parties to recognize the presence of silver and aim at extracting it were G. D. Edwards and party, J. Masters, and A. W. Oakley. The first company to try to extract silver was the Alpha Co.; its methods and machinery were unsuitable and it wound up its affairs and re-formed as the Freiberg Co., which used a new method for trying to save the silver. Nearly every chemist and mine manager had his own theories—or patents—for extracting the silver but none were very successful on St. Arnaud stone.

The Alpha Co. had its lease on the Trinidad and Argentine Reefs, but when it re-formed as the Freiberg, ground on the Warwickshire, Rotten and Queen Semiramis was added.

Brough Smyth gives the figure of silver raised in Victoria prior to December 1866 as 12,513 ounces and states that it came mostly from St. Arnaud. The total output of silver in Victoria has only been 30,577 ounces, worth £7,880... Ten times more than this amount was spent in working the St. Arnaud silver mines. Even the value of the gold raised with the silver did not prevent the failure of the silver-mining companies.

In 1857 the New Chum and Silvermine line of reefs came into the news with dramatic suddenness. The claim of G. D. Edwards, Henry La Roche and E. J. Hynam was at last giving good results. The stone they cut out had always looked promising, but on retorting, they obtained little or nothing. By accident they found the cause of their disappointing results — the metal in their claim was a mixture of gold and silver, the latter in the form of a silver chlorobromide and requiring different treatment from that used to extract only gold. This discovery attracted attention throughout Victoria and was reported in English newspapers, for the discovery was made at the same time as the announcement of the Great Comstock silver lode in the Sierra Nevada. Although no great results were ever obtained from the silver-bearing reefs, the discovery had important results in that it led to outside capital investment in both the silver and gold reefs. By 1860 the best ground on St. Arnaud was in the hands of companies.

From A New Bendigo – The story of the Gold & Silver Mines of St. Arnaud. (2008)[2]

The St Arnaud gold and silver orebodies differed from most other orebodies discovered in the 1850s in eastern Australia. The mineral composition of the ore included the oxides and sulphides of iron, lead, copper, bismuth and manganese, and chlorides and bromides of silver, and was more complex than the free milling orebodies of Clunes, Ballarat, Castlemaine and Bendigo. It was difficult and costly to separate out the gold and silver, and special methods were introduced and tested and tested with varying success. The complexity of the ore attracted industrial chemists and metallurgists to the field from the late 1850s, but the problems of extracting the gold were not solved until the 1890s and early 1900s as mining technologies improved and experience was gained. The problem of extracting the silver was not solved.

...discovery of rich silver ore at the north end of the field by 1857...

One reef, the Silvermine, which was a northern extension of the Wilson's Hill reefs to the east of Shewrings at New Bendigo, was rich in silver... By 1857 G.D. Edwards, Henry La Roche, and E. Hynam were working the Silvermine reef which ran over Stuart's Hill where a large quartz blow, since removed, stood high above the surface. John Macredie and J. Masters had separate claims on this reef south of Edwards' party. The reef, including the blow, was mined for the high mineral content of silver chlorides and bromides and a small amount of gold... Small amounts of other minerals were to prove troublesome in separating out the gold and silver.

The gold and silver could be extracted by amalgamation with mercury, but the other minerals could not be extracted... The amalgamation was then heated in an iron retort, the mercury was distilled off, leaving the gold in the retort. At St Arnaud the additional minerals, particularly lead, tended to poison the mercury and often made amalgamation difficult.

The Blink Bonny reef... Penberthy bought the mine at a Sherriff's auction on behalf of Charles Sharkey, a local bank manager.

Crushing Plants

By the beginning of 1860 four crushers had been erected at St Arnaud:

Owner

Location

Date

Type

Youngsen

Chrysolite Hill

1856

Stampers purchased by Clow

Macredie

South End

1856

Chilean Mill

McRoberts & Jennings

South End

1858

Chilean Mill

Coleman

King George Pk

1858

Stampers later Butcher & Co

During the 1860s the following plants were erected:

Grierson, Edgar & Co

Chrysolite Hill

1861

Stampers & pumps 10 HP

St Arnaud United Co.

Wilson's Hill

1861

Stampers & pumps 60 HP

C.F. Cameron

Sebastopol reef

1861

Stampers

Alpha Co.

Trinidad reef

1861

Appleton + Balfour crushers

...

...

...

...

Freiberg Co.

ex Alpha Co.

1865

Stampers added

...

...

...

...

James Malcolm... had worked pans designed by Denny, Reilly, Otway and Wheeler but found the Wheeler pan the best.

The second [mining company at St Arnaud] was the Alpha Silver Mining Company... It appears this was a partnership or a cost book company, with the finance coming from Ballarat. Otway was the manager and chemist at the mine. A shaft was dug on the Trinidad reef, north of the township, and the mine dam was built some metres away, in an adjacent gully. This dam was also still in existence, but is now separated from the mine by the Watsons Lake Road and the Donald Railway line. A crushing plant and four reverberatory furnaces were built near the dam. George Ulrich, trained in mining at University level, at the Clausthal Mining Academy in the Harz Mountains in Germany, reported on this mine in 1864 when he was employed by the Geological Survey of Victoria. He had inspected the mine shortly after it had failed in August 1863. Sufficient ore had been mined for one operation of the furnaces (probably several hundred tonnes) but the organisation ran out of money, and the mine was closed down when the first treatment produced little gold or silver.

Ulrich reported the... ore in this reef contained little silver and that galena (lead sulphide) had been mistakenly identified as silver ore. In his conclusion he said it was unlikely that rich silver ores were to be found at depth in these reefs which contained only small amounts of silver near the surface.

The Alpha Co. failed after the trial crushing because it worked the mine for silver although its reef was mainly auriferous.

Legacy

See also

Notes

References

↑ Palmer, Yvonne S (1980). Track of the years : the story of St. Arnaud (3rd ed). St. Arnaud Mercury Print, St. Arnaud, Vic

↑ Birrell, Ralph Winter (2008). A New Bendigo – The story of the Gold & Silver Mines of St. Arnaud." R.W. Birrell, Strathfieldsaye, Victoria, Australia